Antenna



Patented Sept. 8, 1942 ANTENNA Walter 0. Spoon, Goldendale, Wash.,assignor of one-half to George S. Klein, Goldendale, Wash.

Application February 8, 1941, Serial No. 378,050

3 Claims.

This invention relates generally to radio receivers and particularly toan antenna.

The main object of thi invention i to construct a loop antenna of thenonresonant, low impedance type.

The second object is to construct an antenna of the type mentioned whichwould be extremely rugged and easy to construct and having a totalabsence of body capacity effect, as well as having a reduced antennaeffect or vertical effect, which makes for sharper tuning, thus makingit an ideal loop for marine use as a radio compass.

The third object is to construct an antenna of the class described whichis equally adaptable for use on the lower frequencies as well as thehigher frequencies, thereby-eliminating the necessity of separate loopsfor each wave band.

The fourth object is to construct an antenna which is especiallyadaptable as a direction finder for aircraft work, since it ope-rates atground potential and so needs no shielding, thereby reducing rain staticto a minimum and also reducing losses due to high impedance conductorsrunning through shielding.

The fifth object is to construct an antenna of the class described whichis especially useful in connection with the receivers in geophysicalprospecting equipment of the radio balance type, due to the entireabsence of body capacity effect. When so used, the wabble so common'inthe high impedance loops when carrying the receiver over rough ground,is eliminated. It also reduces the capacity effect of vegetation.

The sixth object is to construct a loop of the class described which isadapted for use on under-water equipment such as submarines because itis always at ground potential and at low impedance, capacity due towater has little or no efiect on its operation.

The seventh object is to construct an antenna of the class describedwhich is easily adaptable for automotive mounting as the metallic carbody produces little capacity effect.

The eighth object is to produce an antenna of the class described havinga precision adjustment for the balancing of the loop.

These and other objects are accomplished in the manner set forth in thefollowing specification as illustrated in the accompanying drawing, inwhich:

Fig. 1 is a front elevation of the antenna showing a matching circuit toa conventional radio receiver.

Fig. 2 is a plan of Fig. 1.

Fig. 3 is a horizontal section taken along the line 33 in Fig. 1.

Fig. 4 is a fragmentary section along the line 44 in Fig. 2.

Similar numerals refer to similar parts throughout the several views.

Referring in detail to the drawing, there is shown a loop base 10 ofsuitable insulating material, preferably one of the forms of plastic nowbeing employed for such purposes.

Into the base In extend the ends H of a tubular loop l2 which iscircular in form. Extending across the diameter of the loop l2 andaxial- 1y into the base I!) is a brass center rod I3, one end of whichis connected by means of a lead M l to a ground l5, and the other end ofwhich passes through a slot 16 in the tubing l2 and is threaded toreceive the lock nut I1 and the cap nut l8.

The purpose of the slot It is to permit the rod E3 to be moved towardeither side of the center of the loop in order to provide an exceedinglydelicate adjustment for the balancing of the loop thereby compensatingfor any errors which might arise due to the variations in the gauge anddiameter of the tubing in the loop I2. This tubing is preferably ofcopper and the size and diameter of the loop depend upon theapplicationlarger tubing and greater diameter of loop giving greatersignal pick-up, and smaller tubing and smaller loop diameter giving lesspick-up.

A matching circuit [9 to a conventional radio receiver 20 is alsoindicated.

While this loop is especially useful for radio compasses and similarinstruments, no special application of the antenna is shown as the useof such devices is well understood.

Where the loop I2 is to be rotated, it is mounted on a revolvable base2! such as are in common use on directional loops, and having acalibrated dial for angular measurements (not shown).

It is a well known fact that various forms of loop antenna have beenconstructed in the past. It is therefore not my intention to cover suchdevices broadly, but I do intend to cover all such forms andmodifications as fall fairly within the appended claims.

I claim:

1.'An antenna of the class described consisting of a base of insulatingmaterial, a circular, upright antenna loop having its lower portiondivided to form two spaced ends and having the ends thereof mounted insaid base and having a grounded rod connecting the upper portion of saidloop to said base and means for laterally adjusting the connectionbetween said grounded rod and the uppermost portion of said loop.

2. A loop of the class described consisting of a circular metallic tubemounted in an upright plane, the lower portion of said tube beingseparated and the ends thereof mounted in a revolvable support ofinsulating material, a grounded rod extending vertically through thediameter of said loop from said support to the upper portion of the loopand means for adjusting the upper end of said grounded rod laterallytoward either side of the center of said loop.

3. A device of the class described consisting of a revolvable base ofinsulating material, a vertical grounded rod mounted in the top of saidbase, a circular loop of tubular metal mounted in a vertical planehaving the lower portion thereof divided and mounted in said base, andhaving the upper portion thereof attached to the upper end of saidgrounded rod, with the grounded rod substantially along the verticaldiameter of the loop and means for adjusting the relationship betweensaid grounded rod and loop.

WALTER O. SPOON.

